ethyl 5-chloro-1-(3-chlorophenyl)-1H-pyrazole-4-carboxylate synthesis

Yield:98534-74-8 80%.

Reaction Conditions:

in chloroform;

Steps:

3.B B.

B. 5-Chloro-1-(3-chlorophenyl)-1H-pyrazole-4-carboxylic acid, ethyl ester Nitrosyl chloride was bubbled into a cold solution of 10.0 g of 5-amino-1-(3-chlorophenyl)-1H-pyrazole-4-carboxylic acid, ethyl ester in 150 ml of chloroform for 20 minutes. The reaction mixture was then placed on a steam bath for five minutes and the volatiles were removed under reduced pressure. The residue was recrystallized from ethanol to afford 7.8 g of 5-chloro-1-(3-chlorophenyl)-1H-pyrazole-4-carboxylic acid, ethyl ester. Yield 80%. mp=61°-63° C. Analysis calculated for C₁₂ H₁₀ Cl₂ N₂ O₂ Theory: C, 50.55; H, 3.54; N, 9.82; Found: C, 50.78; H, 3.29; N, 10.04.

References:

US4620865,1986,A